1. Technical Field
The present invention relates to a single coil dual solenoid valve, i.e., a solenoid valve with a single magnetic coil and two plungers (two valve bodies).
2. Background Art
Formerly, in order to secure redundancy in prevention of leakage of a gas from a burner whose combustion operation is being stopped, a combustion apparatus is so arranged that two solenoid valves are interposed in series in a gas supply passage and that, even if one of the solenoid valves fails to be closed, the other of the solenoid valves can prevent the gas from leaking (see, for example, JP-1998-2446 A).
According to this prior art arrangement, there is provided a solenoid in each of the solenoid valves. It follows that two solenoid valves with two solenoids are required, resulting in an increase in the occupying space and the electric power consumption. Therefore, this prior art arrangement cannot meet the recent requirements for downsizing and electric power saving.